[Intel-gfx] [PATCH v2 02/22] drm/i915/dp: Track the pipe and link bpp limits separately

[Luca Coelho]

On Thu, 2023-08-24 at 11:04 +0300, Imre Deak wrote:
> A follow-up patch will need to limit the output link bpp both in the
> non-DSC and DSC configuration, so track the pipe and link bpp limits
> separately in the link_config_limits struct.
> 
> Use .4 fixed point format for link bpp matching the 1/16 bpp granularity
> in DSC mode and for now keep this limit matching the pipe bpp limit.
> 
> v2: (Jani)
> - Add to_bpp_int(), to_bpp_x16() helpers instead of opencoding them.
> - Rename link_config_limits::link.min/max_bpp to min/max_bpp_x16.
> 
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  .../drm/i915/display/intel_display_types.h    | 10 ++++++++
>  drivers/gpu/drm/i915/display/intel_dp.c       | 25 +++++++++++--------
>  drivers/gpu/drm/i915/display/intel_dp.h       |  9 ++++++-
>  drivers/gpu/drm/i915/display/intel_dp_mst.c   | 17 ++++++++-----
>  4 files changed, 44 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 731f2ec04d5cd..5875eff5012ce 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h

[...]

> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
> index 788a577ebe16e..ebc7f4e60c777 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -26,7 +26,14 @@ struct intel_encoder;
>  struct link_config_limits {
>  	int min_rate, max_rate;
>  	int min_lane_count, max_lane_count;
> -	int min_bpp, max_bpp;
> +	struct {
> +		/* Uncompressed DSC input or link output bpp in 1 bpp units */
> +		int min_bpp, max_bpp;
> +	} pipe;
> +	struct {
> +		/* Compressed or uncompressed link output bpp in 1/16 bpp units */
> +		int min_bpp_x16, max_bpp_x16;
> +	} link;
>  };

It's not clear to me from the commit message (nor from the code, for
that matter) why you need to store the values in both formats.  Can you
clarify?

--
Cheers,
Luca.